1. Field of the Invention
The present invention relates to a belt molding mounted to an upper edge portion of an automotive door panel. More particularly, the invention relates to a belt molding configured such that a design tape having gloss, such as a metallic gloss or a highly lustered color, is affixed (adhered or fusion-bonded) to the outer surface of a molding body made of a hard resin, along the longitudinal direction of the molding body.
2. Description of the Related Art
A belt molding configured such that a design tape is provided on the outer surface of a molding body along the longitudinal direction of the molding body is manufactured by a method described in, for example, Japanese Patent No. 3798657.
In order to meet demands on metal-cored moldings to reduce weight and cost, an attempt has been made to provide a design tape having gloss, such as a metallic gloss or a highly lustered color, on the outer surface of a belt molding made of a hard resin. FIGS. 4A to 4C show an example belt molding 1P having a design tape 13P. FIG. 4A is a sectional view taken along line S-S of FIG. 3B. Notably, the belt molding 1P of FIGS. 4A to 4C and a belt molding 1Q (which will be described later) of FIGS. 5A and 5B are those which had been studied in the process of devising belt moldings 1, 1A, and 1B of the present invention, and do not constitute prior art. The belt moldings 1P and 1Q partially include constituent elements of the present invention.
The belt molding 1P includes a molding body made of a hard resin (PP) and having an elongated outer wall 11P and an inner wall 12P extending downward from an upper edge portion of the outer wall 11P; a design tape 13P affixed, by fusion bonding or the like, along the longitudinal direction to an upper region of the outer surface of the outer wall 11P; an upper seal lip 15P made of a soft resin (TPO) and standing from an upper edge portion of the inner wall 12P in the vicinity of the upper edge portion of the outer wall 11P; a lower seal lip 16P made of a soft resin (TPO) and standing from a lower portion of the inner wall 12P; an upper tongue 17P made of a soft resin (TPO) and standing from a substantially central portion of the inner surface of the outer wall 11P; and a lower tongue 18P made of a soft resin (TPO) and extending from the lower end of the outer wall 11P.
The belt molding 1P is mounted to an automotive door panel 2 (see FIG. 3B) in such a manner as to nip an upper edge portion of the door panel 2 in a gap between the outer wall 11P and the inner wall 12P. By this procedure, the upper seal lip 15P and the lower seal lip 16P come in elastic, slidable contact with a window glass (not shown). Also, the upper tongue 17P and the lower tongue 18P come in elastic contact with the outer surface of the upper edge portion of the outer panel. Notably, PP is polypropylene, and TPO is thermoplastic polyolefin.
(1) First Problem (Wrinkles and Shrinkage)
The above-mentioned belt molding 1P is manufactured as follows: while the molding body (the outer wall 11P and the inner wall 12P) is being extrusion-molded, the upper seal lip 15P, the lower seal lip 16P, the upper tongue 17P, and the lower tongue 18P are extrusion-molded and fusion-bonded to corresponding regions of the molding body (the outer wall 11P and the inner wall 12P) for integration with the molding body; at the same time, the design tape 13P wound in roll is fed to be affixed to the outer surface of the outer wall 11P by fusion bonding or a like method. Thus, at the time when the design tape 13P is affixed to the outer wall 11P made of PP, the upper seal lip 15P, the lower tongue 18P, etc., made of TPO are in such a molten state as to allow fusion-bonding thereof to the molding body made of PP.
Meanwhile, in view of design, the design tape 13P affixed to the outer wall 11P must be covered at its opposite edge portions with certain members while as large an apparent width as possible is secured. This is for the following reason: if an edge of the design tape 13P of a product is exposed, the design tape 13P is apt to come off from the exposed edge, and a misaligned edge, if any, looks unattractive. In order to cope with this problem, in the example of FIGS. 4A and 4B, an upper edge portion 131P of the design tape 13P is covered with a root portion of the upper seal lip 15P made of TPO, and a lower edge portion of the design tape 13P is covered with an upper edge portion of a TPO layer 1110P.
However, when the above-mentioned practice is employed, as shown in the enlarged view of FIG. 4B, the distal end of the upper edge portion 131P of the thin design tape 13P protrudes into TPO which is in such a molten state as to allow fusion-bonding, and may move in a supportless condition. As a result, wrinkles form in the upper edge portion 131P; the wrinkles are propagated from the upper edge portion 131P toward the center of the width of the design tape 13P; and an exposed design surface suffers from an appearance defect, such as wrinkles. An object of the present invention is to prevent the occurrence of such an appearance defect. By contrast, a portion of the design tape 13P in the vicinity of the lower edge portion of the design tape 13P covered with the TPO layer 1110P is free from formation of wrinkles, since that portion is affixed to the outer wall 11P made of PP.
FIG. 4C shows an example measure to prevent formation of the above-mentioned wrinkles. In FIG. 4C, an upper edge portion of the design tape 13P is bent and affixed to the surface of an upper edge portion of the inner wall 12P. The bent, affixed portion is denoted by 131PP. However, this raises another problem of difficulty in peeling off a protection film. That is, at the time of shipment, the surface of the design tape 13P is covered with a protection film; thus, after manufacture of the belt molding, the protection film must be peeled off. Specifically, the belt molding extruded from an extrusion-molding machine is cooled and cut into pieces each having a predetermined length; then, the protection film must be peeled off. At this time, the bent, affixed portion 131PP causes difficulty in peeling off the protection film. An attempt to forcibly peel off the protection film causes, for example, breakage of a root portion of the upper seal lip 15P. Therefore, the method shown in FIG. 4C cannot be employed.
(2) Second Problem
Next will be described another problem involved in a belt molding in which a design tape having gloss, such as a metallic gloss or a highly lustered color, is affixed. In the belt molding having the design tape affixed, in order to prevent an appearance defect (distortion of a reflection image (flaring appearance) stemming from uneven or nonuniform reflectional direction), a surface to which the design tape is to be affixed must have high flatness and smoothness. When the surface to which the design tape is to be affixed is even slightly poor in flatness and smoothness, uneven or nonuniform reflectional direction causes the distortion of a reflection image (in actuality, the “reflection image” is not so clear as to be said to be an image), resulting in so-called flaring appearance. Therefore, the surface must have high flatness and smoothness. However, an attempt to achieve such high flatness and smoothness is very costly.
Another object of the present invention is to sufficiently restrain the distortion of a reflection image (flaring appearance) stemming from uneven or nonuniform reflectional direction without involvement of a great increase in cost, for a belt molding having an affixed design tape having gloss, such as a metallic gloss or a highly lustered color.
(3) Belt Molding of FIGS. 5A and 5B
Problems (wrinkles and shrinkage, and flaring appearance) to be solved by the present invention have been described above with reference to the belt molding 1P of FIGS. 4A to 4C. Next, problems to be solved by the present invention will be described with reference to a belt molding 1Q of FIGS. 5A and 5B. Similar to FIG. 4A, FIG. 5A is a sectional view taken along line S-S of FIG. 3B. The letter P is a suffix indicative of the belt molding of FIGS. 4A to 4C. Similarly, the letter Q is a suffix indicative of the belt molding of FIGS. 5A and 5B. As for numerals appearing in figures, FIGS. 4A to 4C and FIGS. 5A and 5B use like numerals for equivalent structural portions or members. The following description covers only features different from those of FIGS. 4A to 4C.
The belt molding 1Q shown in FIG. 5A includes a molding body made of a hard resin (PP) and having an elongated outer wall 11Q and an inner wall 12Q extending downward from an upper edge portion of the outer wall 11Q; a design tape 13Q affixed along the longitudinal direction to a lower region of the outer surface of the outer wall 11Q; a lower tongue 18Q made of a soft resin (TPO) and extending from the lower end of the outer wall 11Q; an upper seal lip 15Q made of a soft resin (TPO) and standing from an upper edge portion of the inner wall 12Q; a lower seal lip 16Q made of a soft resin (TPO) and standing from a lower portion of the inner wall 12Q; and an upper tongue 17Q made of a soft resin (TPO) and standing from a substantially central portion of the inner surface of the outer wall 11Q. Similar to the belt molding 1P, the belt molding 1Q is also mounted to the automotive door panel 2 (see FIG. 3B) in such a manner as to nip an upper edge portion of the door panel 2 in a gap between the outer wall 11Q and the inner wall 12Q.
As is understood from comparison between FIGS. 4A to 4C and FIGS. 5A and 5B, in the belt molding 1Q of FIGS. 5A and 5B, the design tape 13Q is affixed to a lower region of the outer wall 11Q; thus, the above-mentioned problem of wrinkles and shrinkage (the first problem) arises on a side toward a lower edge portion 131Q of the design tape 13Q. Except for this, the belt molding 1Q is similar to the belt molding 1P of FIGS. 4A to 4C. As for flaring appearance (the second problem), the belt molding 1Q is similar to the belt molding 1P of FIGS. 4A to 4C.
In FIGS. 4A to 4C (FIGS. 5A and 5B), since the width of the design tape 13P (13Q) is narrower than that of the outer wall 11P (11Q), the design tape 13P (13Q) is affixed to an upper region of the outer wall 11P (a lower region of the outer wall 11Q). As a result, the problem of wrinkles and shrinkage (the first problem) arises on a side toward the upper edge portion 131P of the design tape 13P (on a side toward the lower edge portion 131Q of the design tape 13Q). However, needless to say, in the case of using a design tape having a width substantially equal to that of the outer wall, the problem of wrinkles and shrinkage (the first problem) arises on both sides toward an upper edge portion and a lower edge portion of the design tape.